A pronoun pointing all over the place...
On the bus this morning two women were talking. One asked the other what she'd done this weekend, and this exchange took place:
A: I watched the thirtieth anniversary of MASH.Wow. Check it out.
B: Which did they show?
A: All of them. You know some of them have gone on. I loved that show.
The pronoun "they" is used three times, and it has a different referent every time. One of those referents is outside the text - the last one; it refers to the actors. The first one refers to the television station that was running the shows. The second refers to the 'which', which is to say to 'episodes'.
And what's truly astonishing, when you think about it, is that neither I nor either woman hesitated a second to assign the proper referents. I'll bet even Watson couldn't have told that the "they" who had gone on wasn't the same "they" in "all of them" - or that that wasn't a peculiar sentence possibly contradicting the first.
Language processing is an amazing thing.